I'm going abroad, and I've downloaded some offline maps that allow me to use the GPS to pinpoint my location. My questions are: 1. Do I need a cellular connection for the GPS to work? I know it's an assisted GPS, so cellular connection speeds up finding your location, but is it essential? 2. If a cellular connection is required, will it come under 'roaming' if my iPhone uses cell towers abroad to help pinpoint my location, costing me money? I'll be turning data roaming and mobile internet off, along with 3G etc to avoid any surprise costs.